2 * metadata/gc.c: GC icalls.
4 * Author: Paolo Molaro <lupus@ximian.com>
6 * (C) 2002 Ximian, Inc.
13 #include <mono/metadata/gc-internal.h>
14 #include <mono/metadata/threads.h>
15 #include <mono/metadata/tabledefs.h>
16 #include <mono/metadata/exception.h>
17 #define GC_I_HIDE_POINTERS
18 #include <mono/os/gc_wrapper.h>
21 #define HIDE_POINTER(v) (v)
22 #define REVEAL_POINTER(v) (v)
25 typedef struct DomainFinalizationReq {
28 } DomainFinalizationReq;
30 #ifdef PLATFORM_WINCE /* FIXME: add accessors to gc.dll API */
31 extern void (*__imp_GC_finalizer_notifier)(void);
32 #define GC_finalizer_notifier __imp_GC_finalizer_notifier
33 extern int __imp_GC_finalize_on_demand;
34 #define GC_finalize_on_demand __imp_GC_finalize_on_demand
37 static int finalize_slot = -1;
39 static gboolean gc_disabled = FALSE;
41 static CRITICAL_SECTION finalizer_mutex;
43 static GSList *domains_to_finalize= NULL;
45 static HANDLE gc_thread;
47 static void object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*));
50 static void finalize_notify (void);
51 static HANDLE pending_done_event;
52 static HANDLE shutdown_event;
56 * actually, we might want to queue the finalize requests in a separate thread,
57 * but we need to be careful about the execution domain of the thread...
60 run_finalize (void *obj, void *data)
62 MonoObject *exc = NULL;
64 o = (MonoObject*)((char*)obj + GPOINTER_TO_UINT (data));
66 if (finalize_slot < 0) {
68 for (i = 0; i < mono_defaults.object_class->vtable_size; ++i) {
69 MonoMethod *cm = mono_defaults.object_class->vtable [i];
71 if (!strcmp (cm->name, "Finalize")) {
78 mono_domain_lock (o->vtable->domain);
80 o2 = g_hash_table_lookup (o->vtable->domain->finalizable_objects_hash, o);
82 mono_domain_unlock (o->vtable->domain);
85 /* Already finalized somehow */
88 /* make sure the finalizer is not called again if the object is resurrected */
89 object_register_finalizer (obj, NULL);
90 /* speedup later... and use a timeout */
91 /* g_print ("Finalize run on %p %s.%s\n", o, mono_object_class (o)->name_space, mono_object_class (o)->name); */
93 /* Use _internal here, since this thread can enter a doomed appdomain */
94 mono_domain_set_internal (mono_object_domain (o));
96 mono_runtime_invoke (o->vtable->klass->vtable [finalize_slot], o, NULL, &exc);
99 /* fixme: do something useful */
104 * Some of our objects may point to a different address than the address returned by GC_malloc()
105 * (because of the GetHashCode hack), but we need to pass the real address to register_finalizer.
106 * This also means that in the callback we need to adjust the pointer to get back the real
108 * We also need to be consistent in the use of the GC_debug* variants of malloc and register_finalizer,
109 * since that, too, can cause the underlying pointer to be offset.
112 object_register_finalizer (MonoObject *obj, void (*callback)(void *, void*))
118 /* This assertion is not valid when GC_DEBUG is defined */
119 g_assert (GC_base (obj) == (char*)obj - offset);
122 if (mono_domain_is_unloading (obj->vtable->domain) && (callback != NULL))
124 * Can't register finalizers in a dying appdomain, since they
125 * could be invoked after the appdomain has been unloaded.
129 mono_domain_lock (obj->vtable->domain);
132 g_hash_table_insert (obj->vtable->domain->finalizable_objects_hash, obj,
135 g_hash_table_remove (obj->vtable->domain->finalizable_objects_hash, obj);
137 mono_domain_unlock (obj->vtable->domain);
139 GC_REGISTER_FINALIZER_NO_ORDER ((char*)obj - offset, callback, GUINT_TO_POINTER (offset), NULL, NULL);
144 mono_object_register_finalizer (MonoObject *obj)
146 /* g_print ("Registered finalizer on %p %s.%s\n", obj, mono_object_class (obj)->name_space, mono_object_class (obj)->name); */
147 object_register_finalizer (obj, run_finalize);
151 * mono_domain_finalize:
153 * Request finalization of all finalizable objects inside @domain. Wait
154 * @timeout msecs for the finalization to complete.
155 * Returns: TRUE if succeeded, FALSE if there was a timeout
159 mono_domain_finalize (MonoDomain *domain, guint32 timeout)
161 DomainFinalizationReq *req;
166 * No need to create another thread 'cause the finalizer thread
167 * is still working and will take care of running the finalizers
173 done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
175 req = g_new0 (DomainFinalizationReq, 1);
176 req->domain = domain;
177 req->done_event = done_event;
179 EnterCriticalSection (&finalizer_mutex);
181 domains_to_finalize = g_slist_append (domains_to_finalize, req);
183 LeaveCriticalSection (&finalizer_mutex);
185 /* Tell the finalizer thread to finalize this appdomain */
188 res = WaitForSingleObject (done_event, timeout);
190 //printf ("WAIT RES: %d.\n", res);
191 if (res == WAIT_TIMEOUT)
196 /* We don't support domain finalization without a GC */
202 ves_icall_System_GC_InternalCollect (int generation)
212 ves_icall_System_GC_GetTotalMemory (MonoBoolean forceCollection)
219 return GC_get_heap_size () - GC_get_free_bytes ();
226 ves_icall_System_GC_KeepAlive (MonoObject *obj)
236 ves_icall_System_GC_ReRegisterForFinalize (MonoObject *obj)
240 object_register_finalizer (obj, run_finalize);
244 ves_icall_System_GC_SuppressFinalize (MonoObject *obj)
248 object_register_finalizer (obj, NULL);
252 ves_icall_System_GC_WaitForPendingFinalizers (void)
257 if (!GC_should_invoke_finalizers ())
260 if (GetCurrentThread () == gc_thread)
261 /* Avoid deadlocks */
264 ResetEvent (pending_done_event);
266 /* g_print ("Waiting for pending finalizers....\n"); */
267 WaitForSingleObject (pending_done_event, INFINITE);
268 /* g_print ("Done pending....\n"); */
273 static CRITICAL_SECTION allocator_section;
274 static CRITICAL_SECTION handle_section;
275 static guint32 next_handle = 0;
276 static gpointer *gc_handles = NULL;
277 static guint8 *gc_handle_types = NULL;
278 static guint32 array_size = 0;
281 * The handle type is encoded in the lower two bits of the handle value:
295 * FIXME: make thread safe and reuse the array entries.
298 ves_icall_System_GCHandle_GetTarget (guint32 handle)
307 EnterCriticalSection (&handle_section);
308 g_assert (type == gc_handle_types [handle >> 2]);
309 obj = gc_handles [handle >> 2];
310 LeaveCriticalSection (&handle_section);
314 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK))
315 return REVEAL_POINTER (obj);
323 ves_icall_System_GCHandle_GetTargetHandle (MonoObject *obj, guint32 handle, gint32 type)
330 EnterCriticalSection (&handle_section);
331 /* Indexes start from 1 since 0 means the handle is not allocated */
333 if (idx >= array_size) {
336 guint8 *new_type_array;
339 new_array = GC_MALLOC (sizeof (gpointer) * (array_size * 2));
340 new_type_array = GC_MALLOC (sizeof (guint8) * (array_size * 2));
343 memcpy (new_array, gc_handles, sizeof (gpointer) * array_size);
344 memcpy (new_type_array, gc_handle_types, sizeof (guint8) * array_size);
345 /* need to re-register links for weak refs. test if GC_realloc needs the same */
346 for (i = 0; i < array_size; ++i) {
347 #if 0 /* This breaks the threaded finalizer, by causing segfaults deep
348 * inside libgc. I assume it will also break without the
349 * threaded finalizer, just that the stress test (bug 31333)
350 * deadlocks too early without it. Reverting to the previous
351 * version here stops the segfault.
353 if ((gc_handle_types[i] == HANDLE_WEAK) || (gc_handle_types[i] == HANDLE_WEAK_TRACK)) { /* all and only disguised pointers have it set */
355 if (((gulong)new_array [i]) & 0x1) {
357 if (gc_handles [i] != (gpointer)-1)
358 GC_unregister_disappearing_link (&(gc_handles [i]));
359 if (new_array [i] != (gpointer)-1)
360 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(new_array [i]), REVEAL_POINTER (new_array [i]));
365 gc_handles = new_array;
366 gc_handle_types = new_type_array;
368 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support built-in"));
372 /* resuse the type from the old target */
375 h = (idx << 2) | type;
378 case HANDLE_WEAK_TRACK:
379 val = (gpointer)HIDE_POINTER (val);
380 gc_handles [idx] = val;
381 gc_handle_types [idx] = type;
383 if (gc_handles [idx] != (gpointer)-1)
384 GC_GENERAL_REGISTER_DISAPPEARING_LINK (&(gc_handles [idx]), obj);
386 mono_raise_exception (mono_get_exception_execution_engine ("No weakref support"));
390 gc_handles [idx] = val;
391 gc_handle_types [idx] = type;
394 LeaveCriticalSection (&handle_section);
399 ves_icall_System_GCHandle_FreeHandle (guint32 handle)
401 int idx = handle >> 2;
402 int type = handle & 0x3;
406 EnterCriticalSection (&handle_section);
409 g_assert (type == gc_handle_types [idx]);
410 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
411 if (gc_handles [idx] != (gpointer)-1)
412 GC_unregister_disappearing_link (&(gc_handles [idx]));
415 mono_raise_exception (mono_get_exception_execution_engine ("No GCHandle support"));
418 gc_handles [idx] = (gpointer)-1;
419 gc_handle_types [idx] = (guint8)-1;
420 LeaveCriticalSection (&handle_section);
424 ves_icall_System_GCHandle_GetAddrOfPinnedObject (guint32 handle)
427 int type = handle & 0x3;
432 EnterCriticalSection (&handle_section);
433 obj = gc_handles [handle >> 2];
434 g_assert (gc_handle_types [handle >> 2] == type);
435 LeaveCriticalSection (&handle_section);
436 if ((type == HANDLE_WEAK) || (type == HANDLE_WEAK_TRACK)) {
437 obj = REVEAL_POINTER (obj);
438 if (obj == (MonoObject *) -1)
448 static HANDLE finalizer_event;
449 static volatile gboolean finished=FALSE;
451 static void finalize_notify (void)
454 g_message (G_GNUC_PRETTY_FUNCTION ": prodding finalizer");
457 SetEvent (finalizer_event);
461 collect_objects (gpointer key, gpointer value, gpointer user_data)
463 GPtrArray *arr = (GPtrArray*)user_data;
464 g_ptr_array_add (arr, key);
468 * finalize_domain_objects:
470 * Run the finalizers of all finalizable objects in req->domain.
473 finalize_domain_objects (DomainFinalizationReq *req)
477 MonoDomain *domain = req->domain;
479 while (g_hash_table_size (domain->finalizable_objects_hash) > 0) {
481 * Since the domain is unloading, nobody is allowed to put
482 * new entries into the hash table. But finalize_object might
483 * remove entries from the hash table, so we make a copy.
485 objs = g_ptr_array_new ();
486 g_hash_table_foreach (domain->finalizable_objects_hash,
487 collect_objects, objs);
488 //printf ("FINALIZING %d OBJECTS.\n", objs->len);
490 for (i = 0; i < objs->len; ++i) {
491 MonoObject *o = (MonoObject*)g_ptr_array_index (objs, i);
492 /* FIXME: Avoid finalizing threads, etc */
496 g_ptr_array_free (objs, TRUE);
499 //printf ("DONE.\n");
500 SetEvent (req->done_event);
502 /* FIXME: How to delete the event ? */
506 static guint32 finalizer_thread (gpointer unused)
510 mono_thread_new_init (GetCurrentThreadId (), &stack_start, NULL);
513 /* Wait to be notified that there's at least one
516 WaitForSingleObject (finalizer_event, INFINITE);
518 if (domains_to_finalize) {
519 EnterCriticalSection (&finalizer_mutex);
520 if (domains_to_finalize) {
521 DomainFinalizationReq *req = domains_to_finalize->data;
522 domains_to_finalize = g_slist_remove (domains_to_finalize, req);
523 LeaveCriticalSection (&finalizer_mutex);
525 finalize_domain_objects (req);
528 LeaveCriticalSection (&finalizer_mutex);
532 g_message (G_GNUC_PRETTY_FUNCTION ": invoking finalizers");
535 /* If finished == TRUE, mono_gc_cleanup has been called (from mono_runtime_cleanup),
536 * before the domain is unloaded.
538 * There is a bug in GC_invoke_finalizer () in versions <= 6.2alpha4:
539 * the 'mem_freed' variable is not initialized when there are no
540 * objects to finalize, which leads to strange behavior later on.
541 * The check is necessary to work around that bug.
543 if (GC_should_invoke_finalizers ()) {
544 GC_invoke_finalizers ();
547 SetEvent (pending_done_event);
550 SetEvent (shutdown_event);
556 * Enable or disable the separate finalizer thread.
557 * It's currently disabled because it still requires some
558 * work in the rest of the runtime.
560 #define ENABLE_FINALIZER_THREAD
562 #ifdef WITH_INCLUDED_LIBGC
564 extern void mono_gc_stop_world (void);
565 extern void mono_gc_start_world (void);
566 extern void mono_gc_push_all_stacks (void);
568 static void mono_gc_lock (void)
570 EnterCriticalSection (&allocator_section);
573 static void mono_gc_unlock (void)
575 LeaveCriticalSection (&allocator_section);
578 static GCThreadFunctions mono_gc_thread_vtable = {
586 mono_gc_push_all_stacks,
589 #endif /* WITH_INCLUDED_LIBGC */
591 void mono_gc_init (void)
593 InitializeCriticalSection (&handle_section);
594 InitializeCriticalSection (&allocator_section);
596 InitializeCriticalSection (&finalizer_mutex);
598 #ifdef WITH_INCLUDED_LIBGC
599 gc_thread_vtable = &mono_gc_thread_vtable;
602 #ifdef ENABLE_FINALIZER_THREAD
604 if (getenv ("GC_DONT_GC")) {
609 finalizer_event = CreateEvent (NULL, FALSE, FALSE, NULL);
610 pending_done_event = CreateEvent (NULL, TRUE, FALSE, NULL);
611 shutdown_event = CreateEvent (NULL, TRUE, FALSE, NULL);
612 if (finalizer_event == NULL || pending_done_event == NULL || shutdown_event == NULL) {
613 g_assert_not_reached ();
616 GC_finalize_on_demand = 1;
617 GC_finalizer_notifier = finalize_notify;
619 /* Don't use mono_thread_create here, because we don't want
620 * the runtime to wait for this thread to exit when it's
623 gc_thread = CreateThread (NULL, mono_threads_get_default_stacksize (), finalizer_thread, NULL, 0, NULL);
624 if (gc_thread == NULL) {
625 g_assert_not_reached ();
630 void mono_gc_cleanup (void)
633 g_message (G_GNUC_PRETTY_FUNCTION ": cleaning up finalizer");
636 #ifdef ENABLE_FINALIZER_THREAD
637 ResetEvent (shutdown_event);
641 /* Finishing the finalizer thread, so wait a little bit... */
642 /* MS seems to wait for about 2 seconds */
644 * FIXME: This is not thread safe. If the finalizer thread keeps
645 * running, and the runtime is shut down, it will lead to a crash.
647 WaitForSingleObject (shutdown_event, 2000);
655 /* no Boehm GC support. */
656 void mono_gc_init (void)
658 InitializeCriticalSection (&handle_section);
661 void mono_gc_cleanup (void)